1. Technical Field
The present disclosure relates to a switch-driving circuit. More particularly, the present disclosure relates to a switch-driving circuit for driving a full-controlled power switch component.
2. Description of Related Art
In the area of a high-power electronic device (e.g., an industrial computer, a server, an electricity equipment, etc), the reliability of the product is required seriously. The mean time between failures (MTBF) is an index used for measuring the reliability of the product. If the electronic device has a longer MTBF, it means that the electronic device is more reliable.
In a traditional power supply of the electronic device, the control signals are usually transmitted via optical fibers to the high-voltage side, so as to control the power switch components at the high-voltage side and the output stage of the power supply. Using the optical fiber transmission instead of an electrical wiring connection may achieve the electrical isolation between the high-voltage side and the low-voltage side, and also between the power switch components at the high-voltage side, so as to avoid the electricity noise interference in between.
However, the optical fibers generally have much shorter MTBF compared to the MTBF of other electronic components within the electronic system. Therefore, the optical fibers become a bottleneck to elevate the reliability of the whole electronic system.
Secondly, each power switch component at the high-voltage side must be isolated from the low-voltage side and isolated from other power switch components at the high-voltage side as well. In this case, each power switch component requires an individual set of optical fibers for transmitting its own control signal. Therefore, the transmission over optical fibers will significantly increase the costs and complexity of the system.
In addition, the signal transmission over optical fibers may lead to longer delay time, such that the synchronization between signals will be poor. When the system requires highly synchronized signals, the signal transmission over optical fibers may cause some issues in the stability of power switch components.
Utilizing a magnetic isolation structure, instead of the optical fibers, for transmitting the driving signal and realizing the electrical isolation can boost the system stability, reduce system costs, simplify the system structure, shorten the delay time and enhance the synchronization between signals, so as to solve most issues existed in the optical fiber isolation structure.
The traditional design of driving circuits coupled to half-controlled power switch components adopt the magnetic isolation structure for transmitting driving signals of switch units. For example, the driving signals at low-voltage side transmits through a transformer, so as to induce triggering pulses to multiple half-controlled power switch components connected in series at the high-voltage side. The Silicon Controlled Rectifier (SCR) is one common example of the half-controlled power switch components.
Based on the characteristic of the half-controlled power switch components, the Silicon Controlled Rectifiers have some requirement on their driving signals: (1) only narrow pulse-width signals are required to trigger and turn on the SCR (the signals for turning off are not necessary, because the half-controlled power switch components can not be turned off through the driving signals); and (2) the pulse transformer can be used to transmit the driving signals and the driving-power at the same time, because the driving signals for the half-controlled power switch components have narrow pulse-widths.
On the other hand, the full-controlled power switch components also have some requirements on their driving signals, which the requirements are different from ones of the half-controlled power switch components, for example: (1) turning on and off the full-controlled power switch component can be controlled by the driving signal; (2) the full-controlled power switch component requires a stable high voltage-level while the switch component is on, and require a stable low voltage-level while it is off; and (3) the driving signal of the full-controlled power switch component must have a longer pulse-width relative to the driving signal of the half-controlled power switch component. Therefore, the driving signal and the driving-power must be transmitted separately on the full-controlled power switch component.
Therefore, the traditional technology for transmitting the driving signal of the half-controlled power switch component can not be applied on the full-controlled power switch component.